Project acronym AAA
Project Adaptive Actin Architectures
Researcher (PI) Laurent Blanchoin
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), LS3, ERC-2016-ADG
Summary Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Summary
Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Max ERC Funding
2 349 898 €
Duration
Start date: 2017-09-01, End date: 2022-08-31
Project acronym C18Signaling
Project Regulation of Cellular Growth and Metabolism by C18:0
Researcher (PI) Aurelio TELEMAN
Host Institution (HI) DEUTSCHES KREBSFORSCHUNGSZENTRUM HEIDELBERG
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary My lab studies how cells regulate their growth and metabolism during normal development and in disease. Recent work in my lab, published last year in Nature, identified the metabolite stearic acid (C18:0) as a novel regulator of mitochondrial function. We showed that dietary C18:0 acts via a novel signaling route whereby it covalently modifies the cell-surface Transferrin Receptor (TfR1) to regulate mitochondrial morphology. We found that modification of TfR1 by C18:0 ('stearoylation') is analogous to protein palmitoylation by C16:0 - it is a covalent thio-ester link and requires a transferase enzyme. This work made two conceptual contributions. 1) It uncovered a novel signaling route regulating mitochondrial function. 2) Relevant to this grant application, we found by mass spectrometry multiple other proteins that are stearoylated in mammalian cells. This thereby opens a new avenue of research, suggesting that C18:0 signals via several target proteins to regulate cellular growth and metabolism. I propose here to study this C18:0 signaling.
To study C18:0 signaling we will exploit tools recently developed in my lab to 1) identify as complete a set as possible of proteins that are stearoylated in human and Drosophila cells, thereby characterizing the cellular 'stearylome', 2) study how stearoylation affects the molecular function of these target proteins, and thereby cellular growth and metabolism, and 3) study how stearoylation is added, and possibly removed, from target proteins.
This work will change the way we view C18:0 from simply being a metabolite to being an important dietary signaling molecule that links nutritional uptake to cellular physiology. Via unknown mechanisms, dietary C18:0 is clinically known to have special properties for cardiovascular risk. Hence this proposal, discovering how C18:0 signals to regulate cells, will have implications for both normal development and for disease.
Summary
My lab studies how cells regulate their growth and metabolism during normal development and in disease. Recent work in my lab, published last year in Nature, identified the metabolite stearic acid (C18:0) as a novel regulator of mitochondrial function. We showed that dietary C18:0 acts via a novel signaling route whereby it covalently modifies the cell-surface Transferrin Receptor (TfR1) to regulate mitochondrial morphology. We found that modification of TfR1 by C18:0 ('stearoylation') is analogous to protein palmitoylation by C16:0 - it is a covalent thio-ester link and requires a transferase enzyme. This work made two conceptual contributions. 1) It uncovered a novel signaling route regulating mitochondrial function. 2) Relevant to this grant application, we found by mass spectrometry multiple other proteins that are stearoylated in mammalian cells. This thereby opens a new avenue of research, suggesting that C18:0 signals via several target proteins to regulate cellular growth and metabolism. I propose here to study this C18:0 signaling.
To study C18:0 signaling we will exploit tools recently developed in my lab to 1) identify as complete a set as possible of proteins that are stearoylated in human and Drosophila cells, thereby characterizing the cellular 'stearylome', 2) study how stearoylation affects the molecular function of these target proteins, and thereby cellular growth and metabolism, and 3) study how stearoylation is added, and possibly removed, from target proteins.
This work will change the way we view C18:0 from simply being a metabolite to being an important dietary signaling molecule that links nutritional uptake to cellular physiology. Via unknown mechanisms, dietary C18:0 is clinically known to have special properties for cardiovascular risk. Hence this proposal, discovering how C18:0 signals to regulate cells, will have implications for both normal development and for disease.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-03-01, End date: 2022-02-28
Project acronym CHROMONUMBER
Project Chromosome number variations in vivo: probing mechanisms of genesis and elimination
Researcher (PI) Renata BASTO
Host Institution (HI) INSTITUT CURIE
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary How variations in whole chromosome number impact organism homeostasis remains an open question. Variations to the normal euploid genome content are frequently found in healthy animals and are thought to contribute with phenotypic variability in adverse situations. Yet they are also at the basis of several human diseases, including neuro-developmental disorders and cancer. Our preliminary data shows that physiological aneuploidy can be identified in certain cells during development. Moreover, we have observed that when induced through mutations, non-euploid cells are effectively eliminated from the cycling population. A quantitative view of the frequency of non-euploid karyotypes and the mechanisms underlying their genesis is lacking in the literature. Further, the tissue specific responses at play to eliminate non-euploid cells, when induced through mutations are not understood. The objectives of this proposal are to quantitatively assess the occurrence of physiological chromosome number variations gaining insight into mechanisms involved in generating it. Additionally, we will identify the tissue-specific pathways involved in maintaining organism homeostasis through the elimination of non-euploid cells. We will use a novel genetic approach to monitor individual chromosome loss at the level of the entire organism, combine it with quantitative methods and state-of-the art-microscopy, and focus on two model organisms - Drosophila and mouse - during development and adulthood. We predict that the findings resulting from this proposal will significantly impact the fields of cell, developmental and animal physiology, generating novel concepts that will bridge the existing gaps in the field, and expand our understanding of the links between karyotype variations, animal development and disease establishment.
Summary
How variations in whole chromosome number impact organism homeostasis remains an open question. Variations to the normal euploid genome content are frequently found in healthy animals and are thought to contribute with phenotypic variability in adverse situations. Yet they are also at the basis of several human diseases, including neuro-developmental disorders and cancer. Our preliminary data shows that physiological aneuploidy can be identified in certain cells during development. Moreover, we have observed that when induced through mutations, non-euploid cells are effectively eliminated from the cycling population. A quantitative view of the frequency of non-euploid karyotypes and the mechanisms underlying their genesis is lacking in the literature. Further, the tissue specific responses at play to eliminate non-euploid cells, when induced through mutations are not understood. The objectives of this proposal are to quantitatively assess the occurrence of physiological chromosome number variations gaining insight into mechanisms involved in generating it. Additionally, we will identify the tissue-specific pathways involved in maintaining organism homeostasis through the elimination of non-euploid cells. We will use a novel genetic approach to monitor individual chromosome loss at the level of the entire organism, combine it with quantitative methods and state-of-the art-microscopy, and focus on two model organisms - Drosophila and mouse - during development and adulthood. We predict that the findings resulting from this proposal will significantly impact the fields of cell, developmental and animal physiology, generating novel concepts that will bridge the existing gaps in the field, and expand our understanding of the links between karyotype variations, animal development and disease establishment.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-07-01, End date: 2022-06-30
Project acronym CYCLODE
Project Cyclical and Linear Timing Modes in Development
Researcher (PI) Helge GROSSHANS
Host Institution (HI) FRIEDRICH MIESCHER INSTITUTE FOR BIOMEDICAL RESEARCH FONDATION
Call Details Advanced Grant (AdG), LS3, ERC-2016-ADG
Summary Organismal development requires proper timing of events such as cell fate choices, but the mechanisms that control temporal patterning remain poorly understood. In particular, we know little of the cyclical timers, or ‘clocks’, that control recurring events such as vertebrate segmentation or nematode molting. Furthermore, it is unknown how cyclical timers are coordinated with the global, or linear, timing of development, e.g. to ensure an appropriate number of cyclical repeats. We propose to elucidate the components, wiring, and properties of a prototypic developmental clock by studying developmental timing in the roundworm C. elegans. We build on our recent discovery that nearly 20% of the worm’s transcriptome oscillates during larval development – an apparent manifestation of a clock that times the various recurring events that encompass each larval stage. Our aims are i) to identify components of this clock using genetic screens, ii) to gain insight into the system’s architecture and properties by employing specific perturbations such as food deprivation, and iii) to understand the coupling of this cyclic clock to the linear heterochronic timer through genetic manipulations. To achieve our ambitious goals, we will develop tools for mRNA sequencing of individual worms and for their developmental tracking and microchamber-based imaging. These important advances will increase temporal resolution, enhance signal-to-noise ratio, and achieve live tracking of oscillations in vivo. Our combination of genetic, genomic, imaging, and computational approaches will provide a detailed understanding of this clock, and biological timing mechanisms in general. As heterochronic genes and rhythmic gene expression are also important for controlling stem cell fates, we foresee that the results gained will additionally reveal regulatory mechanisms of stem cells, thus advancing our fundamental understanding of animal development and future applications in regenerative medicine.
Summary
Organismal development requires proper timing of events such as cell fate choices, but the mechanisms that control temporal patterning remain poorly understood. In particular, we know little of the cyclical timers, or ‘clocks’, that control recurring events such as vertebrate segmentation or nematode molting. Furthermore, it is unknown how cyclical timers are coordinated with the global, or linear, timing of development, e.g. to ensure an appropriate number of cyclical repeats. We propose to elucidate the components, wiring, and properties of a prototypic developmental clock by studying developmental timing in the roundworm C. elegans. We build on our recent discovery that nearly 20% of the worm’s transcriptome oscillates during larval development – an apparent manifestation of a clock that times the various recurring events that encompass each larval stage. Our aims are i) to identify components of this clock using genetic screens, ii) to gain insight into the system’s architecture and properties by employing specific perturbations such as food deprivation, and iii) to understand the coupling of this cyclic clock to the linear heterochronic timer through genetic manipulations. To achieve our ambitious goals, we will develop tools for mRNA sequencing of individual worms and for their developmental tracking and microchamber-based imaging. These important advances will increase temporal resolution, enhance signal-to-noise ratio, and achieve live tracking of oscillations in vivo. Our combination of genetic, genomic, imaging, and computational approaches will provide a detailed understanding of this clock, and biological timing mechanisms in general. As heterochronic genes and rhythmic gene expression are also important for controlling stem cell fates, we foresee that the results gained will additionally reveal regulatory mechanisms of stem cells, thus advancing our fundamental understanding of animal development and future applications in regenerative medicine.
Max ERC Funding
2 358 625 €
Duration
Start date: 2017-10-01, End date: 2022-09-30
Project acronym DissectPcG
Project Dissecting the Function of Multiple Polycomb Group Complexes in Establishing Transcriptional Identity
Researcher (PI) Diego PASINI
Host Institution (HI) UNIVERSITA DEGLI STUDI DI MILANO
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary The activities of the Polycomb group (PcG) of repressive chromatin modifiers are required to maintain correct transcriptional identity during development and differentiation. These activities are altered in a variety of tumours by gain- or loss-of-function mutations, whose mechanistic aspects still remain unclear.
PcGs can be classified in two major repressive complexes (PRC1 and PRC2) with common pathways but distinct biochemical activities. PRC1 catalyses histone H2A ubiquitination of lysine 119, and PRC2 tri-methylation of histone H3 lysine 27. However, PRC1 has a more heterogeneous composition than PRC2, with six mutually exclusive PCGF subunits (PCGF1–6) essential for assembling distinct PRC1 complexes that differ in subunit composition but share the same catalytic core.
While up to six different PRC1 forms can co-exist in a given cell, the molecular mechanisms regulating their activities and their relative contributions to general PRC1 function in any tissue/cell type remain largely unknown. In line with this biochemical heterogeneity, PRC1 retains broader biological functions than PRC2. Critically, however, no molecular analysis has yet been published that dissects the contribution of each PRC1 complex in regulating transcriptional identity.
We will take advantage of newly developed reagents and unpublished genetic models to target each of the six Pcgf genes in either embryonic stem cells or mouse adult tissues. This will systematically dissect the contributions of the different PRC1 complexes to chromatin profiles, gene expression programs, and cellular phenotypes during stem cell self-renewal, differentiation and adult tissue homeostasis. Overall, this will elucidate some of the fundamental mechanisms underlying the establishment and maintenance of cellular identity and will allow us to further determine the molecular links between PcG deregulation and cancer development in a tissue- and/or cell type–specific manner.
Summary
The activities of the Polycomb group (PcG) of repressive chromatin modifiers are required to maintain correct transcriptional identity during development and differentiation. These activities are altered in a variety of tumours by gain- or loss-of-function mutations, whose mechanistic aspects still remain unclear.
PcGs can be classified in two major repressive complexes (PRC1 and PRC2) with common pathways but distinct biochemical activities. PRC1 catalyses histone H2A ubiquitination of lysine 119, and PRC2 tri-methylation of histone H3 lysine 27. However, PRC1 has a more heterogeneous composition than PRC2, with six mutually exclusive PCGF subunits (PCGF1–6) essential for assembling distinct PRC1 complexes that differ in subunit composition but share the same catalytic core.
While up to six different PRC1 forms can co-exist in a given cell, the molecular mechanisms regulating their activities and their relative contributions to general PRC1 function in any tissue/cell type remain largely unknown. In line with this biochemical heterogeneity, PRC1 retains broader biological functions than PRC2. Critically, however, no molecular analysis has yet been published that dissects the contribution of each PRC1 complex in regulating transcriptional identity.
We will take advantage of newly developed reagents and unpublished genetic models to target each of the six Pcgf genes in either embryonic stem cells or mouse adult tissues. This will systematically dissect the contributions of the different PRC1 complexes to chromatin profiles, gene expression programs, and cellular phenotypes during stem cell self-renewal, differentiation and adult tissue homeostasis. Overall, this will elucidate some of the fundamental mechanisms underlying the establishment and maintenance of cellular identity and will allow us to further determine the molecular links between PcG deregulation and cancer development in a tissue- and/or cell type–specific manner.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-11-01, End date: 2022-10-31
Project acronym ETAP
Project Tracing Evolution of Auxin Transport and Polarity in Plants
Researcher (PI) Jiri Friml
Host Institution (HI) INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Call Details Advanced Grant (AdG), LS3, ERC-2016-ADG
Summary Multicellularity in plants evolved independently from other eukaryotes and presents a unique, alternative way how to deal with challenges of life. A major plant developmental module is the directional transport for the plant hormone auxin. The crucial components are PIN auxin transporters, whose polar, subcellular localization determines directionality of auxin flow through tissues. PIN-dependent auxin transport represents a unique model for studying the functional link between basic cellular processes, such as vesicle trafficking and cell polarity, and their developmental outcome at the level of the multicellular organism. Despite decades of intensive research, the classical approaches in the established models are approaching their limits and many crucial questions remain unsolved, in particular related to PIN structure, regulatory motifs and evolutionary origin
I propose to start a new direction in my research using an evolutionary perspective. This promises to overcome current limitations and provides not only (i) interesting insights into PIN evolution and diversification, but also (ii) a unique opportunity to study how evolutionary conserved cellular mechanisms of e.g. endocytic trafficking evolved specific plug-ins to make them subject to plant-specific regulations. The characterization of (iii) prokaryotic PIN origin will provide a so urgently needed (iv) entry into PIN structural studies. To achieve these goals, we will also establish novel (v) genetic and cell biological models in the ancestral lineage of the land plants that will be of a great use for any plant evolutionary studies.
The intellectual and methodological challenges of such interdisciplinary strategy combining several lower and higher plant models are obvious, but our preliminary results at several fronts promise its feasibility and success to gain deeper understanding of exciting questions on evolution and mechanisms behind the coordination and specification of developmental programs.
Summary
Multicellularity in plants evolved independently from other eukaryotes and presents a unique, alternative way how to deal with challenges of life. A major plant developmental module is the directional transport for the plant hormone auxin. The crucial components are PIN auxin transporters, whose polar, subcellular localization determines directionality of auxin flow through tissues. PIN-dependent auxin transport represents a unique model for studying the functional link between basic cellular processes, such as vesicle trafficking and cell polarity, and their developmental outcome at the level of the multicellular organism. Despite decades of intensive research, the classical approaches in the established models are approaching their limits and many crucial questions remain unsolved, in particular related to PIN structure, regulatory motifs and evolutionary origin
I propose to start a new direction in my research using an evolutionary perspective. This promises to overcome current limitations and provides not only (i) interesting insights into PIN evolution and diversification, but also (ii) a unique opportunity to study how evolutionary conserved cellular mechanisms of e.g. endocytic trafficking evolved specific plug-ins to make them subject to plant-specific regulations. The characterization of (iii) prokaryotic PIN origin will provide a so urgently needed (iv) entry into PIN structural studies. To achieve these goals, we will also establish novel (v) genetic and cell biological models in the ancestral lineage of the land plants that will be of a great use for any plant evolutionary studies.
The intellectual and methodological challenges of such interdisciplinary strategy combining several lower and higher plant models are obvious, but our preliminary results at several fronts promise its feasibility and success to gain deeper understanding of exciting questions on evolution and mechanisms behind the coordination and specification of developmental programs.
Max ERC Funding
2 410 292 €
Duration
Start date: 2018-01-01, End date: 2022-12-31
Project acronym GasPlaNt
Project Gas sensing in plants: Oxygen- and nitric oxide-regulated chromatin modification via a targeted protein degradation mechanism
Researcher (PI) Daniel James GIBBS
Host Institution (HI) THE UNIVERSITY OF BIRMINGHAM
Call Details Starting Grant (StG), LS3, ERC-2016-STG
Summary Oxygen (O2) and nitric oxide (NO) are gases that function as key developmental and stress-associated signals in plants. Investigating the molecular basis of their perception has the potential to identify new targets for crop improvement. In previous ground breaking work I showed that the direct transcriptional response to O2/NO is mediated by controlled degradation of specialised ‘gas-sensing’ transcription factors. We have now linked this degradation mechanism to a new functional class of ‘sensor’, a chromatin modifying protein that regulates the epigenetic silencing of genes. Here we will investigate the hypothesis that this protein acts as a previously undiscovered link between O2/NO and chromatin dynamics, and that plants have evolved a unique system for transducing gaseous signals into rapid transcriptional responses, and longer term epigenetic changes, through targeting different types of protein to the same degradation pathway.
Using multidisciplinary genetic, biochemical and omics approaches we will investigate the molecular basis of this novel gas perception system, which appears to be a plant-specific innovation. We will identify its global gene targets (the ‘gas-responsive epigenome’), and uncover its growth and stress-associated functions in Arabidopsis and barley. We will also investigate how manipulating this pathway using genome editing and synthetic biology techniques alters plant performance, focusing on traits of agronomic significance. This ambitious and timely research will take our knowledge of O2/NO-signaling and the control of chromatin dynamics beyond the current state of the art by offering insight into a completely novel signaling mechanism operating at the interface of gas-perception, protein degradation, and epigenetics. GasPlaNt will therefore provide a step-change in our understanding of how plants synchronise their gene expression in response to signals to optimise growth and development within a dynamic environment.
Summary
Oxygen (O2) and nitric oxide (NO) are gases that function as key developmental and stress-associated signals in plants. Investigating the molecular basis of their perception has the potential to identify new targets for crop improvement. In previous ground breaking work I showed that the direct transcriptional response to O2/NO is mediated by controlled degradation of specialised ‘gas-sensing’ transcription factors. We have now linked this degradation mechanism to a new functional class of ‘sensor’, a chromatin modifying protein that regulates the epigenetic silencing of genes. Here we will investigate the hypothesis that this protein acts as a previously undiscovered link between O2/NO and chromatin dynamics, and that plants have evolved a unique system for transducing gaseous signals into rapid transcriptional responses, and longer term epigenetic changes, through targeting different types of protein to the same degradation pathway.
Using multidisciplinary genetic, biochemical and omics approaches we will investigate the molecular basis of this novel gas perception system, which appears to be a plant-specific innovation. We will identify its global gene targets (the ‘gas-responsive epigenome’), and uncover its growth and stress-associated functions in Arabidopsis and barley. We will also investigate how manipulating this pathway using genome editing and synthetic biology techniques alters plant performance, focusing on traits of agronomic significance. This ambitious and timely research will take our knowledge of O2/NO-signaling and the control of chromatin dynamics beyond the current state of the art by offering insight into a completely novel signaling mechanism operating at the interface of gas-perception, protein degradation, and epigenetics. GasPlaNt will therefore provide a step-change in our understanding of how plants synchronise their gene expression in response to signals to optimise growth and development within a dynamic environment.
Max ERC Funding
1 495 341 €
Duration
Start date: 2017-03-01, End date: 2022-02-28
Project acronym GRADIENTSENSING
Project Cellular navigation along spatial gradients
Researcher (PI) Michael Karl Sixt
Host Institution (HI) INSTITUTE OF SCIENCE AND TECHNOLOGY AUSTRIA
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary Gradients of extracellular signalling molecules are a central concept in biology: for example gradients of guidance-cues such as chemokines position migrating cells in development, malignancy and immunity. Because immune cells are permanently motile, their function most critically depends on spatiotemporal orchestration by a large family of chemokines. To specify direction, concentration differences of the chemokine need to be interpreted by the migrating cell. Most mechanistic knowledge about eukaryotic gradient sensing is inferred from the amoeba Dictyostelium discoideum migrating towards soluble gradients of cyclicAMP. The biology of chemokines is much more diverse, e.g. gradients can take different shapes and, importantly, they do not only emerge in the soluble but also in the immobilized phase. In this proposal we suggest to address the principles of leukocyte chemotaxis using convergent system wide, cell biological and intravital approaches. Employing a newly developed, genetically tractable primary leukocyte system, we will test the contribution of spatial and temporal signalling paradigms of gradient sensing. Quantitative microscopy will be used to image cellular responses to engineered immobilized and soluble chemokine gradients of defined shape as well as to optogenetically triggered signals. In a complementary approach we will screen for proteins responding to chemokine signalling and perform the first genome wide genome editing-based loss of function screen for directionally persistent chemotaxis and haptotaxis. Findings will be validated in vivo to guarantee physiological relevance. In a support project we will precision-engineer the genome of primary leukocytes suitable for assaying migration. A unique combination of cellular, genetic, engineering and quantitative microscopy tools will allow this new and holistic approach to a question which is not only fundamental for immunology but also for understanding development and cancer biology.
Summary
Gradients of extracellular signalling molecules are a central concept in biology: for example gradients of guidance-cues such as chemokines position migrating cells in development, malignancy and immunity. Because immune cells are permanently motile, their function most critically depends on spatiotemporal orchestration by a large family of chemokines. To specify direction, concentration differences of the chemokine need to be interpreted by the migrating cell. Most mechanistic knowledge about eukaryotic gradient sensing is inferred from the amoeba Dictyostelium discoideum migrating towards soluble gradients of cyclicAMP. The biology of chemokines is much more diverse, e.g. gradients can take different shapes and, importantly, they do not only emerge in the soluble but also in the immobilized phase. In this proposal we suggest to address the principles of leukocyte chemotaxis using convergent system wide, cell biological and intravital approaches. Employing a newly developed, genetically tractable primary leukocyte system, we will test the contribution of spatial and temporal signalling paradigms of gradient sensing. Quantitative microscopy will be used to image cellular responses to engineered immobilized and soluble chemokine gradients of defined shape as well as to optogenetically triggered signals. In a complementary approach we will screen for proteins responding to chemokine signalling and perform the first genome wide genome editing-based loss of function screen for directionally persistent chemotaxis and haptotaxis. Findings will be validated in vivo to guarantee physiological relevance. In a support project we will precision-engineer the genome of primary leukocytes suitable for assaying migration. A unique combination of cellular, genetic, engineering and quantitative microscopy tools will allow this new and holistic approach to a question which is not only fundamental for immunology but also for understanding development and cancer biology.
Max ERC Funding
1 984 922 €
Duration
Start date: 2017-04-01, End date: 2022-03-31
Project acronym IlluMitoDNA
Project Illuminating the mechanisms of mitochondrial DNA quality control and inheritance
Researcher (PI) Christof OSMAN
Host Institution (HI) LUDWIG-MAXIMILIANS-UNIVERSITAET MUENCHEN
Call Details Starting Grant (StG), LS3, ERC-2016-STG
Summary Essential subunits of the mitochondrial respiratory chain, which generates the majority of energy in eukaryotic cells, are encoded in the mitochondrial genome (mtDNA) that is present in hundreds of copies in every cell. Mutations within mtDNA have been identified as the cause for a multitude of human diseases and have been tightly linked to the ageing process and altered stem cell homeostasis. Accordingly, to ensure organismal health, good copies of mtDNA have to be faithfully inherited during cell division, their integrity needs to be maintained over generations and they need to be distributed throughout the mitochondrial network to provide all mitochondrial segments with mtDNA encoded proteins. Astonishingly, it remains poorly understood how cells accomplish these fundamental tasks.
Through the development of a novel system that for the first time allowed minimally invasive tracking of mtDNA in living cells, we have gained unique insights into the cellular principles that govern distribution and inheritance of mtDNA and the maintenance of its integrity. This work paved the way to understand the molecular mechanisms that underlie these processes and provides the tools required to elucidate them. We will build on this work and combine cutting-edge microscopy and next generation sequencing with biochemical and genetic approaches to identify and characterize the machineries responsible for (1) mtDNA inheritance and distribution and (2) mtDNA quality control. While these first two aims will exploit the unique experimental advantages of S. cerevisiae, our ultimate goal is (3) to transfer our findings to higher eukaryotes through the development of a mammalian mtDNA imaging system.
This powerful multipronged approach will mechanistically unravel mtDNA dynamics and quality control and will thus provide the necessary basis to understand diseases where these processes are dysregulated.
Summary
Essential subunits of the mitochondrial respiratory chain, which generates the majority of energy in eukaryotic cells, are encoded in the mitochondrial genome (mtDNA) that is present in hundreds of copies in every cell. Mutations within mtDNA have been identified as the cause for a multitude of human diseases and have been tightly linked to the ageing process and altered stem cell homeostasis. Accordingly, to ensure organismal health, good copies of mtDNA have to be faithfully inherited during cell division, their integrity needs to be maintained over generations and they need to be distributed throughout the mitochondrial network to provide all mitochondrial segments with mtDNA encoded proteins. Astonishingly, it remains poorly understood how cells accomplish these fundamental tasks.
Through the development of a novel system that for the first time allowed minimally invasive tracking of mtDNA in living cells, we have gained unique insights into the cellular principles that govern distribution and inheritance of mtDNA and the maintenance of its integrity. This work paved the way to understand the molecular mechanisms that underlie these processes and provides the tools required to elucidate them. We will build on this work and combine cutting-edge microscopy and next generation sequencing with biochemical and genetic approaches to identify and characterize the machineries responsible for (1) mtDNA inheritance and distribution and (2) mtDNA quality control. While these first two aims will exploit the unique experimental advantages of S. cerevisiae, our ultimate goal is (3) to transfer our findings to higher eukaryotes through the development of a mammalian mtDNA imaging system.
This powerful multipronged approach will mechanistically unravel mtDNA dynamics and quality control and will thus provide the necessary basis to understand diseases where these processes are dysregulated.
Max ERC Funding
1 851 834 €
Duration
Start date: 2017-08-01, End date: 2022-07-31
Project acronym IniReg
Project Mechanisms of Regeneration Initiation
Researcher (PI) Kerstin BARTSCHERER
Host Institution (HI) KONINKLIJKE NEDERLANDSE AKADEMIE VAN WETENSCHAPPEN - KNAW
Call Details Starting Grant (StG), LS3, ERC-2016-STG
Summary Injury poses a key threat to all multicellular organisms. However, while some animals can fully restore lost body parts, others can only prevent further damage by mere wound healing. Which molecular mechanisms determine whether regeneration is induced or not is an unsettled fundamental question. I will use whole body regeneration, one of the most fascinating biological processes, as an experimental paradigm to identify the mechanisms of regeneration initiation. As a model organism I will employ planarians, flatworms with extraordinary plasticity that regenerate every piece of their body within a few days. I will mechanistically dissect how these animals rapidly induce an efficient regeneration program in response to tissue loss and define the key switches that determine whether a wound regenerates. Combining the astonishing regenerative abilities of planarians with new technologies I will first comprehensively describe the molecular changes occurring during the amputation response. Second, with a powerful novel assay developed in my lab - dormant fragments - that allows for the first time the separation of wounding from tissue loss in a single planarian, I will analyze the dynamics of the earliest regenerative events. Third, I will functionally characterize the regeneration-initiating signals and their target pathways combining in vivo RNAi and phenotypic assays. Fourth, with a regeneration-deficient planarian species, I will test whether the identified key regulators act as network nodes that can be utilized to rescue regeneration. Importantly, using vertebrate paradigms, such as the regenerating zebrafish fin, I will investigate conserved roles of these network nodes and validate general principles of regeneration initiation. This project will not only uncover conserved mechanisms of regeneration initiation but will also identify the switches that must be levered to induce regeneration in non-regenerating animals.
Summary
Injury poses a key threat to all multicellular organisms. However, while some animals can fully restore lost body parts, others can only prevent further damage by mere wound healing. Which molecular mechanisms determine whether regeneration is induced or not is an unsettled fundamental question. I will use whole body regeneration, one of the most fascinating biological processes, as an experimental paradigm to identify the mechanisms of regeneration initiation. As a model organism I will employ planarians, flatworms with extraordinary plasticity that regenerate every piece of their body within a few days. I will mechanistically dissect how these animals rapidly induce an efficient regeneration program in response to tissue loss and define the key switches that determine whether a wound regenerates. Combining the astonishing regenerative abilities of planarians with new technologies I will first comprehensively describe the molecular changes occurring during the amputation response. Second, with a powerful novel assay developed in my lab - dormant fragments - that allows for the first time the separation of wounding from tissue loss in a single planarian, I will analyze the dynamics of the earliest regenerative events. Third, I will functionally characterize the regeneration-initiating signals and their target pathways combining in vivo RNAi and phenotypic assays. Fourth, with a regeneration-deficient planarian species, I will test whether the identified key regulators act as network nodes that can be utilized to rescue regeneration. Importantly, using vertebrate paradigms, such as the regenerating zebrafish fin, I will investigate conserved roles of these network nodes and validate general principles of regeneration initiation. This project will not only uncover conserved mechanisms of regeneration initiation but will also identify the switches that must be levered to induce regeneration in non-regenerating animals.
Max ERC Funding
1 500 000 €
Duration
Start date: 2017-04-01, End date: 2022-03-31
